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One of the most important uses of history is to help predict the future
and avoid the mistakes of the past. When it comes to medical matters,
many people say they would just as soon not know what the future holds.
This might have made sense in the past when a person could not do much
about his medical future. However, we now have lots of options, and based
on what you know of your family's medical history, you may be able to
influence your future health.
For example, of my six grandparents and parents, five died of stroke
or heart attack. My own cholesterol continued to climb in spite of careful
dieting. When I learned that three close relatives also had high readings
I realized this was a hereditary problem. Fortunately, we now have medication
to help even the poor odds that a bad gene might have given us.
If there is a family history of unusual afflictions — even seemingly
benign ones — or many people dying from similar causes, you would
do well to begin investigating. You may find there is simply a predisposition
to one disease and there are precautions that can be taken. Or, you might
find a genetic disorder that you, your children or grandchildren should
seriously investigate before having children.
Predisposition
Some families may be predisposed towards a particular disease. It means
they are not born with it, but a large number of people develop it over
their lifetime. This information can be helpful to you as you can avoid
situations that might bring an early onset of the disease. You can also
be vigilant in watching for potential symptoms and getting early treatment.
For example, if you know you are predisposed towards diabetes, you can
be careful of your diet and make sure you are tested periodically.
Hereditary Genetic Disorders — Kings, Queens, and You
There are many diseases themselves — not just the predisposition
— that can be passed on to a child. In addition, because of race,
sex or other factors, you may be more likely to have this gene. Many,
if not most, of these diseases, such as Tay-Sachs, Cystic Fibrosis, Sickle
Cell Anemia and Huntington's Disease, are terrible, debilitating conditions
that no parent would knowingly want to pass on to a child. While most
manifest themselves at birth or soon thereafter, Huntington's Disease
does not develop until midlife when a person has already passed the gene
on to a child. Woody Guthrie was a victim of the disease as was his mother
and two of his daughters.
Hemophilia is one of the most well-known genetic disorders. It is believed
to have been caused by a gene mutation in Queen Victoria. Her large family
intermarried with many of the royal houses of Europe and members of several
royal houses had it, the most famous being the son of Czar Alexander of
Russia. Czarina Alexandra was so desperate to find a cure that she consulted
the monk Rasputin, a crude and unpopular figure in Russia. The general
disapproval over this association contributed to the unpopularity of the
royal family which eventually lead to the revolution.
Porphyria
is another royal disease with historical implications. One of the symptoms
of this disease is bouts of madness and it is believed that King George
III of England suffered from this genetic disorder which may have gone
back to Mary,
Queen of Scots.
Gathering Information
Genetic testing has made great advances and in many cases a test can
determine if a person is carrying a gene for a particular disease. In
other cases there is no test, so how do you determine if those who have
gone before you had a problem? As with all genealogy, you must use many
resources.
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Death certificates are usually an excellent source, although there
can be problems with them. For example, death certificates recently
issued by New Jersey had the cause of death information blacked out.
Older certificates might use outdated terms, but these can be translated.
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Interviews with relatives may elicit the information or some clues.
They may not have known what Uncle Jack had exactly, but they probably
can tell you if he had terrible headaches or stomach pains, if he
had a lingering illness or died suddenly.
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Obituaries used to tell the cause of death more often than they do
now. However, at the end of the obituary it may say to send donations
to the Cancer Society, Heart Association, etc. which is a very good
clue.
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A doctor might not have had a name for it back then, but a posthumous
diagnosis could be possible now. Sometimes pictures or descriptions
of the person give modern doctors information that let them identify
a disease of a person who died hundreds of years ago. Abraham Lincoln
may have suffered from Marfan Syndrome, an inherited disorder which
probably was not identified when he was alive. (DNA tests, which should
answer this question, are going to be performed on a cloak stained
with Lincoln's blood.) Ikhnaton (Akhenaton), a pharaoh of Egypt is
usually portrayed with a long, horse-faced head and gangly arms, an
indication he probably
also had Marfans. Some believe that the figures in El Greco's
paintings are always so tall and thin because he had a visual impairment
that caused him to see people this way. All of these are guesses,
but illustrate how modern doctors can diagnose a problem centuries
later.
What to Do with the Information
If you are simply predisposed towards a disease, you are mostly limited
to being vigilant. However, there are some rather radical decisions that
families with a predisposition to some types of cancer have been forced
to make. Breast cancer and ovarian cancer can be a very real possibility
if several of a woman's female relatives have had the disease. Some healthy
woman have decided to have mastectomies or hysterectomies since the risk
of getting these cancers was so great.
The odds for many hereditary defects can be accurately predicted through
genetic counseling. People with family histories of these defects should
receive testing and counseling before they have children so that they
can make an intelligent decision on the risks involved.
Ethnic Factors
It is well known that some diseases favor certain ethnicities. Ashkenazi
Jews (Jews of Eastern European descent) stand a far higher statistical
probability of having certain diseases including Gaucher disease, Bloom
syndrome, Canavan disease and Tay-Sachs disease. This higher percentage
probably comes from the history of these people being a small population
who intermarried.
Sickle Cell Anemia occurs more frequently in African Americans. If both
parents have the disease, all their children will have it. If one parent
has it and the other is normal (not a carrier), all the children will
be carriers. (A carrier does not suffer from the disease itself but "carries"
the gene that could pass the disease on to descendants.) In addition,
people of Mediterranean descent more often have thalassemia, and cystic
fibrosis is more often found in persons of central European ancestry.
Some disorders are related to sex, the most famous being hemophilia.
Women can only be carriers of the disease and only men are born with it.
Recessive Genes
How can it happen that two normal, healthy people can have a child with
a hereditary disease? It happens the same way two brown-eyed parents can
have a blue-eyed baby. Each person has two genes that control eye color
but generally the eyes will only be one color. The gene for brown eyes
is dominant over the gene for blue eyes. If a person has one brown-eye
and one blue-eye gene, the brown will dominate over the blue and he will
have brown eyes. However, the blue-eye gene is still there and can be
passed on to a child. If two brown-eyed parents each have a brown-eye
and blue-eye gene and the one the child inherits from each is for blue
eyes, then the child will have blue eyes.
The same thing can happen if the gene causing the disease is recessive.
Both parents could have inherited a healthy gene and a recessive gene
for the disease. Since the healthy gene is dominant, the parents are healthy.
Father has one normal gene (1n) and one for the disease (1d)
Mother has one normal gene (2n) and one for the disease (2d)
There are four possible combinations for any child they have:
1n + 2n = a healthy person with two normal genes
1n + 2d = a healthy person, since the normal gene is dominant,
but a carrier of the disease since the child has one disease gene that
can be passed on
1d + 2n = a healthy person but a carrier
1d + 2d = with no healthy gene to dominate, the child will have the
disease
Predicting the Odds
There are many factors involved depending on which gene carries the defect,
whether the gene is recessive or dominant and whether one or both parents
have the disease or if one or both are carriers. However, in many cases
the odds are completely predictable. If both parents are carriers, as
above, 25% of the children will have the disease, 75% will be healthy
but 50% will be carriers. If the gene is recessive and one parent has
the disease and the other healthy, the children will not have it but all
will be carriers. (Since the parent with the disease had to receive two
genes with the disease in order to have it, he only has the disease ones
to pass on.) These odds apply to each pregnancy. Even if the parents have
a normal child, they need to be aware that the child may be a carrier.
Genetic Counseling
Once you have gathered your family medical history, you should not go
too far in trying to interpret it as you could jump to wrong conclusions.
For example, if the women in your family who had breast cancer were all
on your father's side, doctors say this does not increase your risk of
getting cancer.
If there is a serious genetic defect in your family and you have not
started a family, counseling would be a good idea. First would be the
decision of whether or not to have children at all. For some people a
75% chance of a normal baby sounds good while others would not want to
take a chance on a 25% possibility of a child that could never have a
normal life or might not survive to its first birthday. In the case of
Huntington's Disease, it would be very difficult to not know for many
years whether or not you had passed on the disease. Even if you already
have children, you may need to inform them of the family history and the
fact that they may be carriers.
More and more is being done with genetics. Many of these genetic diseases
will be curable in the future but you will be ahead of the game if you
can identify through family history the areas that might be a problem
for you.
Recording Your Information
Family Tree Maker has a place for you to record medical information and
cause of death. You can also print this information on your charts so
you can easily track the history of a disease once you have collected
the information. It could save your life!
Future Developments
In the future, DNA will provide many of the answers that we have to scramble
so hard now to find from documents and family histories. There are already
organizations encouraging people to leave a sample of their DNA so future
generations can find answers that are not available now. Wouldn't
it have been nice if our ancestors could have left DNA samples that even
today would have provided us with answers to a lot of questions. (Of course,
it might also have proven that they weren't our ancestors!)
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